Circuit interrupter



July 26, 1955 R. H. AMUNDSON CIRCUIT INTERRUPTER 2 Sheets-Sheet 1 Filed April 22, 1953 JNVENTOR. flmun dson Roczld H jm/Q/ July 26, 1955 R. H. AMUNDSON 2,714,144 CIRCUIT INTERRUPTER Filed April 22, 1955 2 Sheets-Sheet 2 INVENTOR. flrnundson States Patent fitice 17%,1144 Patented July 26, 1955 CHRCUIT INTERRUPTER Roald H. Amundsen, Milwaukee, Wis., assignor to McGraW Electric Company, Milwaukee, Wis., a corporation of Delaware Application April 22, 1953, Serial N 0. 350,443 6 Qlaims. (Cl. 200-146) This invention relates to circuit interrupters, and particularly to interrupters that may be used on high tension lines, and which are adapted to be opened under load without damaging integral parts or associated apparatus.

In recent years there have been a number of contributions to the circuit interrupter field that have been diercted to auxiliary interrupting devices operating in conjunction with disconnect switching mechanisms. The auxiliary interrupters are electrically connected in the circuit in parallel relationship to the main switch connection, and are arranged to have the current momentarily transferred thereto during the period that the main switch means is being opened. The auxiliary circuit is arranged to open after a predetermined time delay, and any arcs that might be established on separation of the auxiliary interrupter contacts are properly and effectively extinguished in an arc extinguishing media.

The present invention is directed to a circuit interrupter that may be conveniently used as an auxiliary interrupter means, or for any interrupting duty requiring effective extinction of any possible arcs created on the separation of electrical contacts.

It is an object of the present invention to provide a circuit interrupter which includes separable contact members and an insulating arc cutoff member adapted to be moved in a plane intersecting a plane defined by the separating movement of the said contacts.

It is another object of this invention to provide a circuit interrupter having separable contact members and an insulating arc cutoff member arranged to be moved in a plane intersecting the plane defined by the path of separation of the contact members, and which cutofi member is rotatably positioned relative to said path and arranged to distend and extinguish any arcs created between the contacts during separation.

It is a specific object of the present invention to provide an insulating arc cutoff member for a circuit interrupter which is of tubular construction and which is adapted to rotate in a plane intersecting the plane defined by the path of separation of separable interrupter contact member contained in said interrupter, whereby any arcs created on separation will be distended and extinguished immediately following its creation.

For a more complete understanding of the nature and scope of this invention, reference may be had to the following detailed description taken in connection with the accompanying drawings, in which:

Fig. 1 is a view partly in elevation and partly in diagram of the circuit interrupter in electrical connection with a main switch means interposed in a power line.

Fig. 2 is a longitudinal sectional view of the circuit interrupter.

Fig. 3 is a cross sectional view of the interrupter taken on lines 33 of Fig. 2.

In the drawings, the interrupter, or load break device, is generally denoted by the reference character 1, and is electrically connected to the power line 2 from line terminals 3 and 4, which connection by-passes the main switch means 5. A direct mechanical connection with the switch means 5 is made with an actuator 6 rotatable on a pivot member 7 to a crank 8. The pivot member 7 is integral with the crank 3 and is grooved to receive the hooked end of a tension spring 9. The spring 9, which is shown under tension in Figs. 1 and 2, is attached at the opposite end to a pin 10 projecting from a sectoral supporting plate 11. The plate is attached to a cover plate 12 by means of spaced conventional machine screws 13, which are preferably countersunk to provide a flush fit. Stop members 14 and 15 are provided by integral projections from the plate 11, and are each engageable with the crank 8, as will hereinafter be described.

Referring in particular to Figs. 2 and 3, it will be seen that the crank 3 is directly connected to an insulating arc cutoff member by means of a face plate 21. The shaft portion 22 of the crank is freely rotatable in the bore of a bearing 23 mounted in the cover plate 12. The shaft portion is rotatably supported by a tapered countersunk member 24 imbedded in an insulating contact supis positioned in an opening in the support member 25 and threadingly engages line terminal 3, which is also imbedded in the supporting member 25, being supported at its outer end by a cover plate 27. The are cutoff member 26 is rotatably supported at one end by bearing 28 The are cutoff member is arranged to slidably reend to the tubular insulating housing 31. The housing is provided with a vent opening 32, which provides a means of expelling gases created within the chamber, as will hereinafter be described. The tubular housing member 31 is preferably of an insulating material such as canvas backed Bakelite lined with an arc extinguishing material 34 substantially coextensive therewith.

which will act to cool and distend any arcs formed between the contacts 26 and 29 as will be described In describing the operation of the present invention, it will be assumed that the main switch means 5 is closed to provide a closed electrical circuit in the power line 2. All of the operating parts are in the position shown in Figs. 1, 2 and 3. That is, the auxiliary circuit obvious that the time delay may be provided in any of many ways, such as with a dashpot, or the like (not shown). The time delay is deemed necessary to provide a momentary period between the opening of the main switch means 5 and the separation of the arcing contacts 26 and 29, during which period the main switch means will be opened without damage to integral parts or associated equipment with the entire load being transferred to the load break device. The entire load transferred to the parallel circuit, including the circuit interrupter or load break device 1, will permit any arcing to occur in a media which acts to cool, de-ionize extinguish and expel gaseous products formed therein.

Assuming now that the switch blade of the main switch means 5 is being opened under conventional practice, the blade will cause the actuator 6 to rock the crank 8 on its axis in a clockwise direction, as shown in Fig. 1, against the action of the tension spring 9. During the interval that it takes the pivot member '7 to move the crank 8 from the stop 14 past its center, the main switch means will be opened and the load transferred to the load break device 1. 'When the pivot 7 passes center the crank will provide a quick-break action until it rests at the stop 15 with the arc cutoff member being rotated through the angle described by thestop members 14 and 15. The are cutoff member, which is shown in cross section in Fig. 3, will rotate to cause the movable contact 29 to rise due to the wedging action of the cutoff member against the Wedging surface 49 on the contact 29. The rotation of the cutoff member will cause the contacts 29 and 26 to remain apart, and provide an insulating surface therebetween. In addition, any arcs formed on the separation of the contacts will be considerably distended by the rotational motion and extinguished by cooling, un-ionized vapors and gases formed on contact of the are by the cutoff member 20.

It Will be apparent that other means may be used to cause the relatively concurrent motion of the cutoff member 20 and the separation of the movable contact 29 from the stationary contact 26, which means (not shown) does not require the wedging action described. That is, the separating motion of the movable contact may be tied in directly through linkages with the rotational motion of the crank 8 (not shown). However, the cutoff and separation action described is deemed adequate to provide the desired circuit interruption. It will be apparent that the longitudinal and transverse dimension of the device may be varied considerably without departing from the scope of the invention. That is, in the field of power switching, fiashover distances must be thoroughly considered and reckoned with, and the design of interrupter parts must provide dimensions that will meet this phenomena.

It will be apparent that a novel form of circuit interrupter has been provided which utilizes an insulating arc cutoif means that is arranged to be interposed between separable arcing contacts during the period of separation to effectively extenuate the arc and act to cool, de-ionize and expel any gaseous products produced during arcing.

I claim:

1. A circuit interrupter including a vented tubular housing having an insulating surface defining an axial bore, a first contact communicating with said bore, a second contact contained within said bore and normally releasably engaged in circuit closing position with said first contact, a stationary supporting cylinder coaxially positioned within said bore and having an insulating surface jointly defining an annular arc-extinguishing chamber with the insulating surface of said housing, a tubular rotatable arc cutoff member disposed within said chamber and having its longitudinal axis substantially concentric with the longitudinal axis of said housing and said cylinder, said cutoff member having an insulating surface normally disposed laterally of said contacts and movable to a position disposed between said contacts upon disengagement thereof during circuit opening operations.

2. A circuit interrupter including a vented tubular housing having an insulating surface defining an axial.

bore, a first contact communicating with said bore, a

second contact contained within said bore and normally I releasably engaged in circuit closing position with said first contact, a stationary supporting cylinder coaxially positioned within said bore and having an insulating surface jointly defining an annular arc-extinguishing chambet with the insulating surface of said housing, a tubular rotatable arc cutoff member disposed wi hin said chamber and having its longitudinal axis substantially concentric with the longitudinal axis of said housing and said cylinder, said cutoif member being operatively associated with said contacts to motivate disengagement of the contacts and having an insulating surface normally disposed laterally of said contacts and movable to a position disposed between said contacts upon disengagement thereof during circuit opening operation, at least one of said insulating surfaces comprising an arc-extinguishing material capable of evolving copious quantities of unionized gases in the presence of an arc.

3. A circuit interrupter including a vented tubular housing having an insulating surface defining an axial bore, a first contact communicating with said bore, a second contact contained within said bore and normally releasably engaged in circuit closing position with said first contact, one of said contacts having an angularly disposed wedging surface, a stationary supporting cylinder coaxially positioned within said bore and having an insulating surface jointly defining an annular arc-extinguishing chamber with the insulating surface of said housing, and a tubular rotatable arc cutoff member disposed Within said chamber and having its longitudinal axis substantially concentric with the longitudinal axis of said housing and said cylinder, said cut-off member having an insulating surface engageable with said contact wedging surface to motivate disengagement of said contacts, said surface normally disposed laterally of said contacts and movable to a position disposed between said contacts upon disengagement thereof during circuit opening operation, at least one of said insulating surfaces comprising an arcextinguishing material' capable of evolving copious quantities of un-ionized gases in the presence of an arc.

4. A load break switching mechanism consisting of a main switch means for electrically connecting and disconnecting an electric line and an auxiliary circuit interrupter normally in parallel circuit relation to said main switch'means and adapted to carry the entire load for an interval after said main switch means is operated to disconnect said electric line, said circuit interrupter including a vented tubular housing having an insulating surface defining an axial bore, a first contact communicating with said bore, a second contact contained within said bore and normally releasably engaged in circuit closing position with said first contact, a stationary supporting cylinder coaxially positioned Within said bore and having an insulating surface jointly defining an annular arc-extinguishing chamber with the insulating surface of said housing, a tubular rotatable arc cutoif member disposed within said chamber and having its longitudinal axis substantially concentric with the longitudinal axis of said housing and said cylinder, said cutoff member having an insulating surface normally disposed laterally of said contacts and movable to a position disposed between said contacts upon disengagement thereof during circuit opening operation.

5. A load break switching mechanism consisting of a main switch means for electrically connecting and disconnecting an electric line and an auxiliary circuit interrupter normally in parallel circuit relation to said main switch means and adapted to carry the entire load for an interval after said main switch means is operated to disconnect said electric line, said circuit interrupter including a vented tubular housing having an insulating surface defining an axial bore, a first contact communicating with said bore, a second contact contained within said bore and normally releasably engaged in circuit closing position with said first contact, a stationary supporting cylinder coaxially positioned within said bore and having an insulating surface jointly defining an annular arc-extinguishing chamber with the insulating surface of said housing, a tubular rotatable arc cutoff member disposed within said chamber and having its longitudinal axis substantially concentric with the longitudinal axis of said housing and said cylinder, said cutoff member being operatively associated with said contacts to motivate disengagement of the contacts and having an insulating surface normally disposed laterally of said contacts and movable to a position disposed between said contacts upon disengagement thereof during circuit opening operation, at least one of said insulating surfaces comprising an arc-extinguishing material capable of evolving copious quantities of un-ionized gases in the presence of an are.

6. A load break switching mechanism consisting of a main switch means for electrically connecting and disconnecting an electric line and an auxiliary circuit interrupter normally in parallel circuit relation to said main switch means and adapted to carry the entire load for an interval after said main switch means is operated to disconnect said electric line, said circuit interrupter including a vented tubular housing having an insulating surface defining an axial bore, a first contact communicating with said bore, a second contact contained within said bore and normally releasably engaged in circuit closing position with said first contact, one of said contacts having an angularly disposed wedging surface, a

stationary supporting cylinder coaxially positioned within said bore and having an insulating surface jointly defining an annular arc-extinguising chamber with the insulating surface of said housing, and a tubular rotatable arc cutoif member disposed within said chamber and having its longitudinal axis substantially concentric with the longitudinal axis of said housing and said cylinder, said cutoff member having an insulating surface engageable with said contact wedging surface to motivate disengagement of said contacts, said surface normally disposed laterally of said contacts and movable to a position disposed between said contacts upon disengagement thereof during circuit opening operation, at least one of said insulating surfaces comprising an arc-extinguishing material capable of evolving copious quantities of un-ionized gases in the presence of an arc Heterences (Iited in the file of this patent UNFTED STATES PATENTS 1,804,063 Schweitzer May 5, 1931 2,254,347 Blakesley Sept. 2, 1941 2,262,386 Crabbs Nov. 11, 1941 2,286,131 Wallace et al. June 9, 1942 2,337,889 Harlow et al. Dec. 28, 1943 2,477,837 Strom Aug. 2, 1949 2,493,419 Puffer Jan. 3, 1950 2,599,242 Favre June 3, 1952 

